Here’s a look at the Jason Fabok lenticular cover (in action) to Batman #21. Click on the image to see the effect.

We’ve also got a first look at the standard image for the Fabok-drawn The Flash #21 cover, which will also come in a lenticular version.

As a reminder, here is how DC describes the crossover.

“The Dark Knight and The Fastest Man Alive, the two greatest detectives on any world, unite to explore the mystery behind a certain blood-stained smiley button embedded in the Batcave wall. What starts as a simple investigation turns deadly when the secrets of the button prove irresistible to an unwelcome third party-and it's not who anyone suspects! It's a mystery woven through time, and the ticking clock starts here!”